青柳 徹二¹, 飯田 和成¹, 松尾 賢二¹, 野中 博子², 佐々木 一昭¹, 川畑 健一¹, 梅村 晋一郎³, 弓田 長彦¹, 西垣 隆一郎¹, 梅村 甲子郎⁴

Tetsuji AOYAGI¹, Kazunari IIDA¹, Kenji MATSUO¹, Hiroko NONAKA², Kazuaki SASAKI¹, Kenichi KAWABATA¹, Shin-ichiro UMEMURA³, Nagahiko YUMITA¹, Ryuichiro NISHIGAKI¹, Koshiro UMEMURA⁴

¹東邦大学医学部第1内科, ²東邦大学医学部病理, ³日立製作所基礎研究所, ⁴東邦大学薬学部薬物動態学教室

¹The First Department of Internal Medicine, Toho University, ²Department of Pathology, Toho University, ³Advanced Recearch Laboratory Hitachi, Ltd., ⁴School of Pharmacentical Science, Toho University

キーワード : Experimental Hepatic Tumor, MRMT-1, Sonodynamic Therapy, HpD, Phased Array, Transducer

The effect of sonodynamic therapy on MRMT-1 hepatic tumor implanted to rats was investigated. The rat tumor was treated with focused ultrasound at 750 kHz from a prototype phased array transducer 24 hr after an adiministration of hematoporphyrin derivative (HpD). The focal spot with a peak intensity of 280 W/cm² was scanned laterally in the tumor region resulting in the averaged intensity of 3.5 W/cm² in the region. The echo texture pattern and the size of the tumor were observed with a 7.5 MHz ultrasound imaging system. The tumor size in the groups treated with ultrasound and HpD showed noticable decrease 24, 48 and 72 hr after the treatment. The size decreased by 11.3% and 16.5%, 48 and 72 hr after the treatment, respectively. The texture pattern changed from hypoechoic to hyperechoic after the treatment. Histopathological observation showed that the sonodynamic treatment with HpD caused necrosis of the tumor tissue and cell-balooning. Slight adverse effects were observed on the skin intervening between the tumor and the transducer and on the normal hepatic tissue surrounding the tumor. These results suggest that the sonodynamic therapy has a potential usefulness for the treatment of hepatic tumor.